1. Field of the Invention
The invention relates to a urological resectoscope with a tubular shaft having a fixed optical guide tube, within which there is an optical system.
2. Description of Related Art
Urological resectoscopes, as are disclosed in DE 3603758 A1, are introduced e.g. through the urethra to the working location, commonly the prostate. Cutting is effected at that point with reciprocating movement of the instrument in the longitudinal direction, which is controlled via its carrier by an operating member disposed beyond the proximal end of the tubular shaft. The instrument is generally a cutting loop to which HF is applied but can also be a knife for special applications. Such resectoscopes may also be used for other applications, for instance in the gynaecological field.
In order to be able to make precise cuts with the instrument, e.g. the cutting loop, in the field of view in front of the optical system, the instrument must be reliably guided by means of its carrier with respect to its radial spacing and its angle of rotation whilst ensuring easy longitudinal movability.
The conventional prior art is shown in FIG. 4 of the aforementioned publication. The carrier is mounted with a sliding tube connected to it on the optical system so as to be longitudinally moveable but at a guaranteed radial spacing, namely on the portion of the optical system which projects distally beyond an optical guide tube connected to the resectoscope and serving to reliably guide and mount it.
The circumferential angular guidance is problematic in this construction. The conventional prior art in this connection is illustrated in FIG. 4 of the aforementioned publication. Connected to the optical guide tube and parallel to it is a carrier guide tube, through which the carrier longitudinally moveably passes and which imparts to the carrier the desired rotational location.
Of disadvantage with this conventional prior art is the additionally necessary carrier guide tube, which is provided parallel on the optical guide tube and is connected to it, for instance by soldering and results in a complex construction of the optical guide tube and which is particularly difficult to clean by reason of its small diameter, which is necessary for reliable guidance.